The overall goal of the proposed research is to develop a PET scanner optirnized for whole-body studies which can accumulate twice the number of counts in + the time of conventional PET scanners. PET scanners using BGO (BismuthGermanate) are limited by the maximum amount of activity of FGD (FluoroDeoxyglucose) which can be injected without exceeding the maximum dose to the patient and the fact that essentially all BGO systems are used in 2-D mode (septa inserted), for whole body scanning. PET scanners using NaI(Tl) have the necessary energy resolution in order to permit full 3-D mode without septa, but are limited by the maximum amount which can be injected due to the limited countrate capability. LGSO is a newly developed scintillator which has the high stopping power similar to BGO but at the same time has a high light output as well as a very short decay time relative to both BGO and NaI(Tl), thereby potentially resulting in both good energy resolution and high countrate capability. The proposed research will overcome the limitations of present PET scanners, by permitting septaless, full 3-D operation for body imaging at high countrates and with high sensitivity. PROPOSED COMMERCIAL APPLICATIONS: The proposed research will lead to the development of a PET scanner which is superior to existing PET scanners for routine clinical whole-body tumor surveys using FDG. In addition, the instrument will also be useful for many other PET applications. UGM currently manufactures PET scanners and will add this scanner to its product line.